scholarly journals Criteria of Equality of Modal Frequency of Micromechanical Gyroscopes-Accelerometers Sensitive Elements

2015 ◽  
Vol 10 (1) ◽  
pp. 133
Author(s):  
Boris Konoplev ◽  
Igor Lysenko ◽  
Olga Ezhova
Keyword(s):  
Sensitive Element ◽  
Forced Vibrations ◽  
Vibration Frequencies ◽  
Sense Mode ◽  
Beam Length ◽  
Drive Mode ◽  
Angular Velocities ◽  
The One ◽  
Intrinsic Vibration ◽  
Structural Layer

<p class="zhengwen"><span lang="EN-GB">In this work the topology of the integrated micromechanical sensor of LL-type is developed. Using the condition of equality of modal frequencies of sensitive elements of the micromechanical sensor in both modes along the one axis the criterion of the coincidence is obtained, the criterion of modal frequencies of sensitive elements of the micromechanical sensor in a sense mode along the two axis is obtained, dependences of the ratio of beam length on thickness of a structural layer are showed, the results of numerical simulation of modal frequencies of the micromechanical sensor sensitive element in a drive mode or a sense mode is obtained using the criterion. Using the criterion, it is possible to achieve coincidence of intrinsic vibration frequencies of a sensitive element in a sense mode that provides the same sensitivity to the angular velocities. Coincidence of frequency of forced vibrations in a drive mode with vibration frequencies of a sense mode along both axis of sensitivity can be achieved by using electrostatic elasticity.</span></p>

scholarly journals Design and Analysis of a High-Gain and Robust Multi-DOF Electro-thermally Actuated MEMS Gyroscope

Micromachines ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 577 ◽  
Author(s):  
Muhammad Saqib ◽  
Muhammad Mubasher Saleem ◽  
Naveed Mazhar ◽  
Saif Awan ◽  
Umar Shahbaz Khan
Keyword(s):  
Resonant Frequency ◽  
Analytical Model ◽  
Actuation Voltage ◽  
High Gain ◽  
Sense Mode ◽  
Drive Mode ◽  
Mass System ◽  
Mems Gyroscope ◽  
Flat Region ◽  
Thermally Actuated

This paper presents the design and analysis of a multi degree of freedom (DOF) electro-thermally actuated non-resonant MEMS gyroscope with a 3-DOF drive mode and 1-DOF sense mode system. The 3-DOF drive mode system consists of three masses coupled together using suspension beams. The 1-DOF system consists of a single mass whose motion is decoupled from the drive mode using a decoupling frame. The gyroscope is designed to be operated in the flat region between the first two resonant peaks in drive mode, thus minimizing the effect of environmental and fabrication process variations on device performance. The high gain in the flat operational region is achieved by tuning the suspension beams stiffness. A detailed analytical model, considering the dynamics of both the electro-thermal actuator and multi-mass system, is developed. A parametric optimization is carried out, considering the microfabrication process constraints of the Metal Multi-User MEMS Processes (MetalMUMPs), to achieve high gain. The stiffness of suspension beams is optimized such that the sense mode resonant frequency lies in the flat region between the first two resonant peaks in the drive mode. The results acquired through the developed analytical model are verified with the help of 3D finite element method (FEM)-based simulations. The first three resonant frequencies in the drive mode are designed to be 2.51 kHz, 3.68 kHz, and 5.77 kHz, respectively. The sense mode resonant frequency is designed to be 3.13 kHz. At an actuation voltage of 0.2 V, the dynamically amplified drive mode gain in the sense mass is obtained to be 18.6 µm. With this gain, a capacitive change of 28.11   f F and 862.13   f F is achieved corresponding to the sense mode amplitude of 0.15   μ m and 4.5   μ m at atmospheric air pressure and in a vacuum, respectively.

scholarly journals Comparison between Accelerometer and Laser Vibrometer to Measure Traffic Excited Vibrations on Bridges

2002 ◽  
Vol 9 (1-2) ◽  
pp. 11-18 ◽  
Author(s):  
G. Rossi ◽  
R. Marsili ◽  
V. Gusella ◽  
M. Gioffrè
Keyword(s):  
Modal Analysis ◽  
Measurement Techniques ◽  
Forced Vibrations ◽  
The Other ◽  
Laser Vibrometer ◽  
Threshold Parameter ◽  
Civil Structures ◽  
Low Frequencies ◽  
Acceleration Amplitude ◽  
The One

The use of accelerometer based measurement techniques for evaluating bridge forced vibrations or to perform bridge modal analysis is well established. It is well known to all researchers who have experience in vibration measurements that values of acceleration amplitude can be very low at low frequencies and that a limitation to the use of accelerometer can be due to the threshold parameter of this kind of transducer. Under this conditions the measurement of displacement seems more appropriate. On the other hand laser vibrometer systems detect relative displacements as opposed to the absolute measures of accelerometers. Vibrations have been measured simultaneously by a typical accelerometer for civil structures and by a laser vibrometer equipped with a fringe counter board in terms of velocity and displacements. The accelerations calculated from the laser vibrometer signals and the one directly measured by the accelerometer has been compared.

scholarly journals A Decoupling Design with T-Shape Structure for the Aluminum Nitride Gyroscope

Micromachines ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 244
Author(s):  
Yang ◽  
Si ◽  
Han ◽  
Zhang ◽  
Ning ◽  
...  
Keyword(s):  
Aluminum Nitride ◽  
Microelectromechanical Systems ◽  
Sense Mode ◽  
Drive Mode ◽  
Aln Film ◽  
Shape Structure ◽  
Mems Gyroscopes ◽  
Sense Electrode ◽  
Working Principle ◽  
Novel Design

This paper reports a novel design for the decoupling of microelectromechanical systems (MEMS) gyroscopes. The MEMS gyroscope is based on piezoelectric aluminum nitride (AlN) film, and the main structure is a mass hung by T-shape beams. A pair of parallel drive electrodes are symmetrically placed on the surface of the vertical bar for driving the oscillating mass. A serpentine sense electrode is placed on the lateral bar. When the gyroscope is oscillating in drive mode, charges with equal quantity and opposite sign will be polarized and distributed symmetrically along the lateral bar. These charges neutralize each other at the sense electrode. Therefore, no coupling signals can be detected from the sense electrode. This design can realize the decoupling between the drive mode and sense mode. In this work, the T-shape decoupled structure was designed as the key component of an AlN piezoelectric gyroscope and the whole structure was simulated by COMSOL Multiphysics 5.2a. The working principle of the decoupling is described in detail. Electrical properties were characterized by the dynamic signal analyzer. According to the test results, the drive mode and the sense mode are decoupled. The coefficient of orthogonal coupling is 1.55%.

OUT-OF-PLANE VIBRATIONS OF CURVED NONPRISMATIC BEAM UNDER A MOVING LOAD

2012 ◽  
Vol 18 (6) ◽  
pp. 773-782 ◽  
Author(s):  
Małgorzata Meissner ◽  
Piotr Ruta
Keyword(s):  
Cross Section ◽  
Moving Load ◽  
Variable Cross Section ◽  
Forced Vibrations ◽  
Variable Cross ◽  
Variable Velocity ◽  
Chebyshev Series ◽  
The Finite Element Method ◽  
Out Of Plane ◽  
The One

The forced vibrations of a curved-in-plane nonprismatic beam with a variable cross section and any curvature, generated by a load moving at a variable velocity are analyzed. Approximation with Chebyshev series and a generalized eigentransformation were used to solve the system of the partial differential equations describing the considered problem. The derived equations in their final form enable one to determine displacement and rotation functions for any beam. In order to verify the derived formulas the eigenproblem solution (used in the eigentransformation method) was compared with the one obtained by the finite element method.

Design Optimization for Non-Resonant MEMS Gyroscope

2009 ◽  
Author(s):  
Wei Cui ◽  
Xiaolin Chen ◽  
Wei Xue
Keyword(s):  
Device Performance ◽  
Sense Mode ◽  
Drive Mode ◽  
Resonant Frequencies ◽  
Frequency Matching ◽  
Wide Range ◽  
Mems Gyroscopes ◽  
Capacitive Mems ◽  
Effective Design ◽  
Model Approach

Conventional capacitive MEMS gyroscopes require close matching between the resonant frequencies of drive mode and sense mode. However, the uncertainties in the microfabrication process impair the robustness of the gyroscopes and often lead to unpredictable device performance. This paper analyzes a 4 degree-of-freedom (DOF) non-resonant gyroscope which is less vulnerable to the fabrication perturbations. Unlike the conventional resonant gyroscope which has only one resonant frequency for drive and sense modes, the 4-DOF gyroscope includes two resonant frequencies for each mode. The non-resonant gyroscope design aims to reduce resonance frequency matching, namely to minimize the effect of the inevitable fabrication uncertainties as well as to increase the bandwidth with less sacrifice to the sensitivity. The device performance is analyzed and optimized by the behavior model approach in CoventorWare which significantly accelerates the simulation compared to the traditional finite element method. The optimized non-resonant gyroscope with higher fabrication tolerance as well as enhanced device performance is proven to be an effective design and can be used in a wide range of applications.

Design and simulation of non-resonant 1-DOF drive mode and anchored 2-DOF sense mode gyroscope for implementation using UV-LIGA process

2016 ◽  
Author(s):  
Payal Verma ◽  
Ram Gopal ◽  
M. A. Butt ◽  
Svetlana N. Khonina ◽  
Roman V. Skidanov
Keyword(s):  
Sense Mode ◽  
Drive Mode

A Multiple-Beam Tuning-Fork Gyroscope With High Quality Factors

2009 ◽  
Author(s):  
Ren Wang ◽  
Shiva Krishna Durgam ◽  
Zhili Hao ◽  
Linda Vahala
Keyword(s):  
Tuning Fork ◽  
Rate Sensitivity ◽  
Sense Mode ◽  
Quality Factors ◽  
Drive Mode ◽  
High Quality ◽  
Multiple Beam ◽  
Frequency Split ◽  
Operation Frequency ◽  
Mask Fabrication

This paper reports on the design, fabrication, and testing of a multiple-beam tuning-fork gyroscope featuring high Quality factors (Q). A multiple-beam tuning-fork structure is designed to achieve high Qs in its drive mode and sense mode. The gyroscope is fabricated on a 30μm-thick SOI wafer using a one-mask fabrication process. The measured Qs of the fabricated gyroscope are 162,060 in the drive-mode and 85,168 in the sense mode at an operation frequency of 16.8kHz. Under a frequency split of 6Hz, the prototype device demonstrates a rate sensitivity of 0.02mV/°/sec.

Design and Simulation of a Z-Axis Dual Proof Mass Micromachined Gyroscope with Decoupled Oscillation Modes

2009 ◽  
Vol 60-61 ◽  
pp. 298-302 ◽  
Author(s):  
Xin Yan ◽  
Zhi Chun Ma ◽  
Xu Yuan Chen
Keyword(s):  
Harmonic Analysis ◽  
Modal Analysis ◽  
Proof Mass ◽  
Vibration Characteristics ◽  
Frame Structure ◽  
Sense Mode ◽  
Drive Mode ◽  
Sense Direction ◽  
Oscillation Modes ◽  
Micromachined Gyroscope

In this paper, a Z-axis micromachined gyroscope with a new decoupled design was presented. The gyroscope consists of dual proof mass, sense frame and drive frame structure. The sense frame is constrained in the sense direction and anchored on the substrate, which minimize the influence from the motion of the proof mass in the drive direction. The drive frame is also restricted to oscillate in the drive direction. ANSYS has been used to make modal analysis and harmonic analysis to determine the vibration characteristics of the decoupled gyroscope. We introduce the decoupling ratio (ηDtS) of drive mode to sense mode and the decoupling ratio (ηStD) of sense mode to drive mode to determine the decoupling design. The results show that the drive mode and the sense mode are well decoupled.

Poetry, Prose, and Rhythm

PMLA ◽  
1922 ◽  
Vol 37 (2) ◽  
pp. 293-310
Author(s):  
C. M. Lotspeich
Keyword(s):  
Fundamental Difference ◽  
The Other ◽  
Essential Difference ◽  
Vibration Frequencies ◽  
Border Line ◽  
Science And Art ◽  
Plant Life ◽  
Forms Of Life ◽  
The One

The following study represents an attempt to determine the fundamental difference between poetry and prose and the relation of simple rhythm, or metre, to poetry. The reader should bear in mind that in all branches of science and art distinctions and classifications hold good, as a rule, only in a broad and general way; there are always border-line phenomena that defy classification. For example, we make a general distinction between animal and plant life, and yet of some of the lower forms of life it is difficult to say whether they belong in the one class or in the other. Or again, it is no uncommon thing to hear chemists and physicists dispute regarding the provinces of their respective sciences. And again, rhythm and melody seem to us to be very different things, and yet at bottom they are both rhythm, because differences in pitch depend upon differences in frequency of vibration, and in any melody these vibration frequencies stand in a rhythmical relation to each other. The farther we penetrate into any subject, the more difficult does exact classification become. And so our distinction between poetry and prose must be taken in a rather broad and general way. There are pieces of prose which seem to be highly poetic in nature, and there are poems in which the writer seems to have encroached upon the province of prose. Be this as it may, I believe we can at least say that in this direction lies the field of poetry, in that the field of prose. With this general reservation, then, let us ask the question: What is the essential difference between poetry and prose?

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